There are about 4 million drivers in Mass. Average commute is 10 miles (ballpark). People work 250 days a year, making 500 trips for 5000 miles/yr/person. Total per-year is 20 x 10^9 miles. A rate of .57 per 100M would be about 11 fatalities per year, which is kind of low but within an order of magnitude of the correct answer. If stats have been kept for 50 years, that's 550 deaths, for an uncertainty (1-sigma) of 22 total deaths, meaning the uncertainty in the .57 number is 0.022. So on the high end, it would be about 0.6 per thousand. Tesla had 2 deaths with an uncertainty of 1.44. So yeah, sorry, there's like a 66% chance (and that's being generous) that Autopilot is less safe than our lovely Boston roads.